Currently,
colloidal quantum dots (CQDs)-based photodetectors are
widely investigated due to their low cost and easy integration with
optoelectronic devices. The requirements for a high-performance photodetector
are a low dark current and a high photocurrent. Normally, photodetectors
with a low dark current also possess a low photocurrent, or photodetectors
with reduced dark current possess a reduced photocurrent, resulting
in low detectivity. In this paper, a solution to suppress dark current
and maintain a high photocurrent, i.e., use of poly(methyl methacrylate)
doped with Au nanoparticles (NPs) (i.e., PMMA:Au) as an interlayer
for enhanced-performance tandem photodetectors, is presented. Our
experimental data showed that the dark current through the tandem
photodetector ITO/PEDOT:PSS/PbS:CsSnBr3/ZnO/PMMA:Au/CuSeN/PbS:CsSnBr3/ZnO/Ag is suppressed significantly; meanwhile, a high photocurrent
is maintained after a PMMA:Au interlayer has been inserted between
two subdetectors. The inserted PMMA:Au interlayer acts as storage
nodes for electrons, reducing the dark current through the device;
meanwhile, the photocurrent can be enhanced under illumination. As
a result, the specific detectivity of the tandem photodetector with
35 nm PMMA:Au interlayer was enhanced significantly from 5.01 ×
1012 to 2.7 × 1015 Jones under 300 μW/cm2 532 nm illumination at a low voltage of −1 V as compared
to the device without a PMMA:Au interlayer. Further, the physical
mechanism of enhanced performance is discussed in detail.
In the past few decades, great attention has been paid to the development of IV–VI semiconductor colloidal quantum dots, such as PbSe, PbS and PbSSe, in infrared (IR) photodetectors due to their high photosensitivity, solution-processing and low cost fabrication. IR photodetectors based on field-effect transistors (FETs) showed high detectivity since the transconductance can magnify the drain–source current under certain applied gate voltages. However, traditional lateral FETs usually suffer from low photosensitivity and slow responsivity, which restricts their widespread commercial applications. In this work, therefore, novel vertical FET (VFET) based photodetectors are presented, in which the active layer is sandwiched between porous source electrode and planar drain electrode, resulting to ultrashort channel length. In this way, enhanced photoresponsivity and specific detectivity of 291 A W−1 and 1.84 × 1014 Jones, respectively, can be obtained at low drain–source voltage (VDS) of −1 V and gate voltage (Vg) of −2 V under 100 μW cm−2 illumination intensity, which was better than that of the traditional lateral FET based photodetectors. Therefore, it is promising to fabricate broadband photodetectors with high performance and good stability by this easy approach.
Recently, great attention has been paid to IV–VI colloidal quantum dots (CQDs) for their high photosensitivity, solution processability and low cost. Also, metal halide perovskites are very promising materials to realize the high-performance solution-processed visible-light photodetectors due to their cost-effective manufacturing, tunable absorption and photoluminescence in whole visible spectrum. In this paper, we present solution-processed CQDs-based tandem broadband photodetectors with low dark-current and high-sensitivity by inserting dielectric Polymethyl methacrylate (PMMA) interlayer between two sub-detectors. Our experimental data showed that the tandem broadband photodetector ITO/PEDOT:PSS/CsPbBr3:PbS0.4Se0.6/ZnO/PVK/CsPbBr3:PbS0.4Se0.6/ZnO/Au showed a maximum specific detectivity of 6.8 × 1013 Jones with a responsivity of 27 A W−1 under 57.8 μW cm−2 980 nm illumination. The device performance can be further enhanced by inserting a 50 nm dielectric PMMA layer between the two sub-photodetectors. As the result, the tandem photodetector ITO/PEDOT:PSS/CsPbBr3:PbS0.4Se0.6/ZnO/PMMA(50 nm)/PVK/CsPbBr3:PbS0.4Se0.6/ZnO/Au exhibits a maximum specific detectivity of 1.32 × 1014 Jones with a responsivity of 27.72 A W−1 under 57.8 μW cm−2 of 980 nm laser. Further, the physical mechanisms for the enhanced performance are discussed in detail.
In general, the fabrication of high‐performance, self‐powered broadband photodetectors based on traditional semiconducting thin films is tedious and costly. Here, in this paper a high‐performance, solution‐processed, and self‐powered CH3NH3PbI3 (MAPbI3) nanocrystal based photodetector ITO/MAPbI3/Ag is presented, and it shows broadband photoresponse from the visible to the near‐infrared wavelength region. The pronounced enhanced performance of the photodetector is due to taking the advantage of the built‐in electric field induced by the work function difference of two electrodes. The optimized photodetector shows a responsivity of 4.9 and 1.42 A W−1 with a specific detectivity of 7.6 × 1013 and 1.77 × 1013 Jones under 19 µW cm−2 white light illumination and 26 µW cm−2 808 nm illumination at zero bias, respectively. Therefore, such a concept of simple device geometry and feasible technique will open up a new and promising avenue for the fabrication of self‐powered photodetectors and the development of imaging devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.